This invention relates to a sprocket wheel of the type used on a tracked vehicle.
For a number of years drive sprockets for tracked vehicles have been made from resilient and rubber like materials, and in large commercial type vehicles solid polyurethane sprockets have in the main given good service. The polyurethane type sprockets have good wear characteristics and operate with low noise and vibration levels. It has recently become apparent that this type of sprocket is not adequate for operation in severe abrasive type soil conditions. For operation in such soil condition there has been manufactured a solid cast iron sprocket which has functioned well. Some of the disadvantages of the solid caset iron sprocket became more significant when attempts were made to provide such a sprocket for very large vehicles. Serious problems have been experienced in manufacturing and handling because of the extreme weight. The large diameter small cross-section cast sprocket is fragile and breakage rate is high. The cast iron sprocket and also the sprocket hub to which the sprocket wheel is attached require machining for proper fit, while machining was not necessary with the solid polyurethane sprocket. Warpage of the large sprocket can also render the high cost cast iron sprocket useless.